Electrical energy can be generated at a generator and transported widely to supply electrical loads. As the energy is transported over great distances, the electrical energy may be in the form of a high potential voltage so that power can be delivered at correspondingly low currents to avoid resistive dissipation in the conductors. As the energy comes in proximity to the load, the voltage may be reduced to lower, safer levels. At the load, the electrical energy may be converted to some other form, such as heat, audible music, rotary motion, linear motion, or electromagnetic radiation.
Lights are one type of load that converts electrical energy to electromagnetic radiation. Visible light may result, for example, when electrical current flows through a resistive conductor causing the conductor to heat-up enough to glow. Visible light may also result when electric current arcs between terminals, as in an arc discharge lamp, or when electrons flow across a p-n junction, as in a light emitting diode (LED).
Individual light sources may be combined on a common load circuit that carries a common current so that a single current illuminates multiple light sources simultaneously. Such a load circuit may be referred to as a light string. In some applications, a light string load may include multiple load circuits connected in series and/or parallel.